US2923007A

US2923007A - High gain broad band antenna

Info

Publication number: US2923007A
Application number: US527929A
Authority: US
Inventors: Douglas H Carpenter
Original assignee: JFD Manufacturing CO Inc
Current assignee: JFD Manufacturing CO Inc
Priority date: 1955-08-12
Filing date: 1955-08-12
Publication date: 1960-01-26
Anticipated expiration: 1977-01-26

Description

Jan. 26, 1960 Filed Aug. 12, 1955 D. H. CARPENTER y I HIGH GAIN BROAD BAND ANTENNA 3 Sheets-Sheet 1 IN V EN TOR. M A75 HAVE/VME Jan. 26, 1960 D. H. CARPENTER 2,923,007

HIGH GAIN BROAD BAND ANTENNA 3 Sheets-Sheet 2 Filed Aug. 12, 1955 IN VEN TOR. .Daz/@4.251. aufm/faq fraz/M975 Jan. 26, 1960 D. H. CARPENTER 2,923,007

HIGH GAIN BROAD BAND ANTENNA Filed Aug. 12, 1955 3 Sheets-Sheet 3 l-TGJL .,VENTO R. zada/4s Mouw/ae BY ,MQ

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d, States Paffmf O 2,923,007 rnGH GAIN BROAD BAND ANTENNA Application August 12, 1955,1seria1 No. 527,929

7 claims. (c1. 34a-721) This invention relates to receiving antennaeuseful for television reception of all channels and is particularly directed to such antenna arrays for high-gain broad-band reception over the whole VHF and UHF ranges.`

The VHF television spectrum is divided into two spaced frequency bands, wherein channels 2 to 6 encompass 54 to 88 megacycles and channels 7 to 13 cover 174 to 216 megacycles. There is a gap betweenY the two VHF bandsl of 85 megacycles; Accordingly, since antennae constructions do not employ electronic circuit elements and must rely on their own physical correlations for performance, combinations of various types have heretofore been employed to broad-band or'otherwise receive 'a band of channels.

The present invention'is directed to novel antenna arrangements for receiving all the channelsZvto 13 of the VHF iband, with high gain and uniform reception over the respective channels thereof and also have excellent UHF reception-from the same antenna array encompassing 470 to 890 megacycles. The antennae of the present invention afford sharp picture clarity and reception and high gain of reception, delivering signals to the television receiver at a maximumjsignal-to-noise ratio. Accordingly, trouble-free and snow-free performance is available for outlying areas with respect to television transmitters. Also, the front-to-back ratio of reception versus interference is high. Furthermore, in view of the `uniformity Vof reception over the respective 6 megacycle band width of each channel by the antennae of the present invention, they are outstandinglysuitable for delity of color signal reception.

An important element in the antennae arrays of the present invention includes theuse of a zig-zag or flat plane arrangement tuned for the upper channels ofthe VHF band, namely channels 7 to 13. Such zig-zag, lying in a single plane, is combined with a suitable transmission line interconnection to a high gain low channel VHF band antenna structure such as a folded dipole or conical array, as will ybe setforth hereinafter. The novel combination of the antennae sections of the present inven- ,tion affords excellent high gain reception throughout the VHF range and also in the UHF range, as will be set forth. The antennae further include reflectors and directors or phasing elements of specific characteristics related to the aforesaid basic sections of the antenna to further improve the signal-to-noise ratio, front-to-back reception ratio, as well as minimizing extraneous noise and signal interference.

`It is accordingly an object of the present invention to provide a novel television receiving antenna having relatively high gain and low noise throughout the VHF and UHF bands.

Another object of the present invention is to provide a novel antenna array having substantially uniform reception on any respective television channelto provide high fidelity of color reception. Y,

A further object of the present invention is to provide 8. novel high gain television antenna wherein long range 2 snow-free perfomance andtrouble-fre'e operation result. t Still a further object of the present invention is to provide a -high gain antenna for television reception, utilizing a novel zig-zag receiving section lying in the plane ofV reception.

Still a further objectof the present invention is to provide a novel high gain low-noise broad band television reception antenna Vemploying a zig-zag in conjunction with a low-channel band dipole.

Still a further object of the present invention is to providea novel television antenna with high signal to noise ratio over the whole VHF andUHF bands, employing aV conical low channel element in novel conjunction with a zig-zag for the high VHF channels. These and further objects'ofthe present invention will becomemore apparent in`the` following description of exemplary embodiments thereof, taken in conjunction with the following drawings in which:

Figures 1, 2 and 3 are diagrammatic representations of theoretical considerations in antenna.-

Figure 4 is a diagrammatic representation of the zig-zag antenna of the present invention.V

Figure 5 is a curve of current distribution of the zig-zag antenna of Figure 4. i

Figure 65 is a set of curves illustrating the current distribution in the novel antenna construction represented in Figure 7. i

Figure 7 is a diagrammatic representation of one embodiment of the present invention employing a zig-zag in conjunction with a folded dipole.

Figure 8 is a polar curVeiIIustrating the reception pattern of `antennae in accordance with the present invention such as illustratedin Figures 9l and l0 and as diagrammatically represented in Figure 7. v

Figures 9 and 10 illustrate in perspective preferred embodiments of antennae in accordance with the present invention. p 1

Figures 11 and l2 are further embodiments of antennae in accordance with the present invention.

In the early days of television, only pentode tubes were available for use in RF amplifiers. Considerable gain was realized, but the limiting factor of the usable signal was the amount of noise generated in the first amplifying stage. override this fixed level lbefore any signal could be amplied. As electronic design progressed, balanced triode tubes were used that reduced the amount of gain available but reduced also by a much greater `ratio the amount of internal noise; The balanced triode then became the industrys standard until, in turn, it was superseded by cascode circuitry. Thus, it can be seen that extreme gain was not the objective of design but rather the greatest amount of usable signal through the rst `RF stage.

Ihe receiving antenna Vthus may well be regarded in the same light as electronic amplifying equipment, or as the tuner of a television receiver. Thus, it is vital to regard, in weak signal reception,conditions,`the signal-tonoise ratio of a receiving antenna system. In other words, the amount of the actual signal that can be realized from a receiving antenna is an important criterion for a given television receiver. There are several factors that enter into the ability of an antenna to deliver maximum magnitude with amplified noise to a receiver. In order of their importance, they are as follows: Y l 1) Horizontal polar pattern.

(2) Front-to-back and side ratio.

(3) Terminating impedance.

(4) Forward gain.

(5) Vertical polar pattern.l

The resultant or effective signal-to-noise ratio of a particular antenna is the compounded eiect ofthe live Ice PatentetivJan. 26, 1960y The weak television signal had tov 2,923,007 Y v .v

antenna characteristics hereinabove enumerated. In

fact, an antenna rating Vsystem employing these five characteristics is used in practice, assigning equal eiect to each of the five factors. Thus, as for item 1, the hori zontal polar pattern of a simple folded dipole averages about 50; whereas 10 would be considered the beam width of a perfect antenna. Further, item '2, front-toback and front-to-side ratios, considered together, would have a '-tol voltage ratio or 20 db valuerfor excellent antennas and is a maximum design standard. Next, .item 3, as to terminating impedance, it is the design goal to have the resultantirnpedance of the composite antenna approximate or equal to thatof the transmission line to which it is connected. A ratio of 1:1 is a perfect termination, whereas a maximum of 1.5:1 is the outsideilimit for practical television reception, wherein the standing wave ratio of the signal is still not a problem in 'the reception pattern. A typical transmission `termination used in practice is 300 ohms. p

'The forward gain, item 4, of 'an excellent'antennaA may be rated at' 20 db or a voltage increase of 10 times over that of a simple dipole. The Vvertical polar pattern Ais curve C be made'to correspond to the curve a, a of antenna of Figure 2 and be in the same .direction .or phase (to the left) as curves a, a, it is made oppositetin phase to the central portion b. By suitably reversing the v interconnection .between antennae 17 and 15., vcancellation of the negative signal b occurs; and the resultant high frequency signal would lthereupon basically correspond to the added magnitudes of curve a, a.

In accordance with the present invention, I provide an elective upper VHF .channel antenna element that has a high. signal-to-noise ratio over the effective band in difficult to evaluate in' a particular antenna array, 'as

each antenna combination has Va different gain oreejection value when the vertical polar'angles are considered. 'T he ability ofv antenna to reject man-madeinterference and, more important, the fixed noise levels from 'different antenna angles, contributes to the overall signal-to-noise ratio of an array. A figure of 10 db rejection or a vvoltage ratio of 3.25 to l is considered excellent for antenna arrays.

Thus, -if each of the five stated antenna characteristics were given equal Weight, or a 20% value where it matches the stated optimum figures hereinabove outlined, an effective signal-to-noise value of 100% would result. It is the purpose of the present invention to provide novel antenna arrays that approach the best Aoverall signal-tonoise factor in most respects over a broad band or wide reception of signal frequencies. Some antennae of 'the prior art, such as single lchannel yagi type, haveV excellent signal-to-noise ratios. However, the present invention is concerned basically with an antenna that has a cluding channels 7 to'l3. Figure 4 illustrates diagrammatically the antenna element 20 which I term a flat plane zig-zag. The zig-zag 20 employs an effective dipole comprised of

elements

21, 22 connected separately and centrally to a transmission line 23.v The zig-zag section is in a single'plane which in the antenna is a line inthe direction `of reception, pointing in thel direction .0f the arrow '24. In the prior art, complex space-consuming and expensive actual circular zig-zag arrangements were used. However, the yflat or plane zig-zag 20 is simple-'to construct and mount lon an antenna pole and relanvely'inexpensive, yet as efective as more complex arrays.

The -zig-zgag 20, as rwill be more fully described and illustrated in'connection with Figures 9` through 12, em-

high gain throughout channels 2 to 13 of the VHF band and good reception throughout the UHF channels. YThe present invention employs some of the good features of a single channel =or yagi type antenna lin combination with other factors to -broad-band it and maintain its gain and signal-tonoise and other excellent characteristics throughout the television channels.

Figure 1 illustrates a simple dipole antenna '15 wherein signals are picked off or otherwise connected to its central portion by transmission leads 16. Figure 1 illustrates the current distribution curve A for the dipole 15 which is at a maximum at the one-half wave length frequency, dependent on the length of the dipole 15. The dipole 15 for' the low channels 2 'to' 6 would provide good reception over the lower channels and a good design center for the dipole would be about channel 3. Nevertheless, when the 'dipole 15 is subjected to the upper band VHF frequencies,-namely those of channels 7 through 13, a current `distribution corresponding to curve B results with respect to the dipole las shown'in Figure 2. Typically, channel 9 has a center frequency of 189 megacycles which is exactly threetimesthe center frequency of 63 megacycles of channel 3. p

Curve B is representative of the three half-wave current'curves onfa lower channel or low channel dipole 15 for reception of :the higher bands impinging thereon. The upper curves a, a add up in one direction and: the central curve b in the opposite direction. Accordingly, the gain at the upper"bands'corresponding to curve B, when added together attransmission lead 16is only equivalent to one of the upper half-waves 11,' as the lower half wave b is in the Opposite directionV and cancelsLout one ofthe upper a signals. Thus, a'low'frequency. an-

bodies a tapered array of

rhombus elements

25, 26, and 27 extending from the Vtriangular initial dipole element 28 and terminating in a similar'triangular element'29. The `successive arms ofthe elements 25 through 29 of zig-zag unit V20 are electrically integral and composed

ofvconductive rods

30, 30 that are either at or hollow as desired. The rods 30 as will be described are pivotally connected at theirrespective joining or cross-over portions. The

outward corners

31 and 32 of the zig-zag 20 are tapered'toward the central axis 33 in the direction away from the

dipole elements

21, 22, namely towards the front. While the Zig-zag 20 is composed of three

rhombus units

25, 26 and 27 and two

triangular units

28, 29, it is to'be understood that other .arrangements and combinations thereof are feasible with equivalent results.

The zig-zag 20 configuration is effective to broadband reception by itself over channels 7 through 13. The cross-over points 35 of the zig-zag element are preferably electrically interconnected and in the preferred embodiments illustrated in VFigures 9 through 12 are grounded to the supporting pole'of the zig-zag 20 along the axis 33 thereof and to the antenna ground structure. The terminus points of

dipole element

21, 22 is, ofcourse, insulated from the antenna structure and connected to the transmission leads 23.

Figure 5 illustrates the current distribution curve"D of the at plane zig-zag 20 proportioned for the upper VHF band encompassing 174 to 2-16 megacyclestchannels 7 through 13). It will be noted that curve Dis of a significantly larger amplitude than that of the simple dipole 17 represented-by curve C of Figure 3 and its current phase in the same direction as that of curve C. Accordingly, should the zig-zag 20 be substituted for the dipole 17, in the reverse phase interconnection withithe low 'frequency dipole 15, an effective additional gain occurs in the additive .section with the currents rz, n of curve B, resulting-in a far lgreater high channel-overall v signal gain. Towards this end, a composite antenna in accordance with the present invention is diagrammatically illustrated in Figure 7, with the composite Vcurrent distribution curve therefor illustrated in Figure 6.

An exemplary embodiment of an all-channel highgain broad-band antenna array in accordance with the present invention is A illustrateddiagrarrimaticallyin Figure`7. The zig-zag 20 corresponding to that of Figure 4 is in a single flat plane and is designed to have maximum gain and effect in the upper VHF band encompassing channels 7 through 1 3. The length of the

front dipole section

21, 22 thereof together with the size of the lirst triangle Vsection 28 to the first cross-over point 35' has a special significance with respect to the low frequency antenna section, as will be set forth. The low frequency band, encompassing channels 2 to 6, is in the embodiment of Figure 7 received officially by the folded dipole 40 having a flat continuous loop open and insulated at its terminal section 41 which is connected to the balanced transmission line 42 to the television receiver (not shown).

The folded dipole has a current distribution of received signals in the low band channels 2 to 6 corresponding to that of a simple open dipole 15, as shown in Figure 2, curve B. However, the folded configuration of dipole 40 emphasizes the gain and provides a greater signal input to transmission line 42 as is well understood by those skilled in the art. In accordance with the present invention, the at zig-zag 20 is interconnected with the folded dipole 40 by the transmission element or harness 45 having terminal leads 43, -43 connecting to the terminals 41, 41 centrally of dipole 40 and the lead ends 23, 23 connecting to the terminals of the dipole section 2'1, 22 of zig-zag 20. It is to be noted that the transmission 'element 45 is reversed 180 between the

leads

43 and 23 thereof. This 180 reversal for the interconnection of

antennae

20 and 40 results in the cancellation `of the negative or reverse high frequencies b shown in Figure 2 when the composite antenna array provides signal reception in the upper channels 7 to 13 to transmission line 42, as well as in the UHF channel band.

A feature of the antenna of Figure 7 is that on channels 2 through 6 the folded dipole or low frequency element 40 operates independently of the zig-zag 20 and provides a high signal in the lower channels to the transmission line 42. The effective reception of the low channels 2 to 6 by the zig-zag 20 is small and accordingly does not materially contribute to that as received and transmitted by the basic low channel element, the folded dipole 40. However, as set forth above, the proportioning of the length of the' harness 45 interconnecting the antenna 20 with dipole 40 as well as the physical design of the

dipole

21, 22 of zig-zag 20 and the size of the first triangle 28 thereof to the first crossover point 35 is such as to provide a stub reflecting a high impedance at the terminals 41, 41 of the folded dipole 40. Thus, the effect of the connected zig-zag 20 to the dipole 40 at channels 2 to 6 is negligible and the operation of the folded dipole for the lower channels is practically independent of the interconnected zig-'zag 20 thereto.

On the upper band channels 7 to 13, however, the effect of the zig-zag 20 corresponding to the curve D of Fig- -ure 5 is superimposed upon the normal curve corresponding to curve B (Figure 2) that the low frequency antenna 40 would have for the upper channels and results in the curve F, F of Figure 6 at the higher frequencies. In other words, the negatively phased high frequency signals corresponding to curve b (Figure 2) normally at the center of the folded dipole for the high channels is negative and otherwise rendered ineifective by the greater signal corresponding to curve D (Figure 5 for the upper channels by zig-zag 20; and the additive curves F, F of Figure 6 results in a high signal value or gain for channels 7 to 13 due to the composite reception of the

antenna section

20 and 40 to transmission line 42.

channels 2 to 6, in combination with the zig-zag array 20` interconnected therewith by transmission line 45 with a reversal. The low frequency antenna 40 operates effectively with high gain over channels 2 to 6 without .interference or electrical intereifects from the interconnected zig-zag Z0, whereas at the upper channels 7 to 13, the zig-zag 20 combines effectively with the reception of the channels 7 to 13 by the basic low frequency array,

namely the folded dipole 40, to provide a high gain for the channels 7 to 13. It has also been found by experimentation and eld measurements that the composite antenna array of Figure 7 also provides very effective gain for the UHF channels 14 through 83, namely in the 470 to 890 megacycle range, with a high signal-to-noise ratio and a gain comparable to that of the low channels 2 to 6 thereof.

A further important advantage of the antenna arrays of the present invention is the high front or side-to-back signal ratios to minimize interference and other deleterious effects in reception. Figure 8 is a polar diagram showing the reception pattern of the antenna array of Figure 7, as well as those of the other embodiments of the invention to be described in connection with Figures 9 and 12. The polar lobe P in the direction of reception corresponding to arrow 46 is a maximum in the direction of reception of the signals with respect to antenna 7, as indicated by arrow 46 in both figures. It is noticed that it is very significant in the signal direction with high gain and tapers off sharply in the other angular directions. The rearward pattern Q of Figure 8 shows the attenuated and low sensitivity of the antenna arrays to the rearward direction. Such excellent polar reception characteristic of the antenna array of the invention coupled with the high gain and low signal noise provides interference-free reception due to man-made interference or other channels or frequencies in directions opposite to the signal direction 46.

Figure 9 illustrates a practical exemplary embodiment of an antenna array corresponding to the diagrammatic illustration of Figure 7, embodying the zig-zag 20 and the folded dipole 40 thereof. The zig-zag 20 is structurally mounted on a metallic bar 50 extending from the mount of antenna pole 51, also of conducting material such as aluminum. The cross-bar 50 is suitably joined to the pole 51 and oriented in a horizontal plane and in the axial direction of reception 46. The

antennae sections

20 and 40 are interconnected by the harness 45 partially seen in Figure 9. -It is to be understood electrically the equivalent to the interconnection at 45 shown in Figure 7 and including the terminal leads 44, 44 of the transmission line 42. The zig-zag antenna 20 is center grounded across its cross-over points 35, 35 connected mechanically to the cross bar 50 which, in turn, is mechanically and electrically connected to the vertical mount 51 of the antenna, in turn grounded.

As is well known, a folded dipole such as 40 has a resonant point determined by its transverse length. It is also well known in the art that the gain of any dipole including such a folded one remains substantially fixed over a much greater frequency range above its resonant point as compared to those frequencies below. Thus, for broad band considerations or for reception of channels 2 to 6 it is preferred that the design point for the effective length of folded dipole 40 be slightly above the frequency for channel 3, namely about 66 to 68 megacycles.

In conjunction with such preferred frequency forthe dipole 40, a pair of

reflectors

52 and 53 is added behind the dipole 40 away from signal direction 46. The reflectors are conductive elements. electrically and mechanically secured at 54 and 55, respectively, to the cross' beam 50 of the antenna structure.

inthe. exemplary embodiment, the half-wave orresonantfrequency forreector- 52-is at the channel 2 frequeues/.audimat of Q reflector 53.atthe,channel 3 frequency.` The.function1of.lthese.reflectorsis-to change the impedanceV as, seen at,the folded dipole. terminals backnto `the transmission line, value. on channel 4, as we1las the gapv between,channels 4'and 5.V ln other words, with a. top, of, channel 3"'frequency for the dipole 40, and ai channel 2 reflector at 52,*,the provision ofthe channel 3'rell'ector 53"`evens out the eifective impedance appearingat the leads 444-ofltransrnission line 4210 the desired valuefurthen across channel 4 and inthe gap covering vfrequencies-72m 76 megacyrcles upto channel 5; Afrther resonant transverse element 56 is added tothe antenna arrayl off Figure 9"in the direction behind that of the signal ,'direction.46 and namely between the folded dipole 40`and the zig, zag4 20. The element-56 may be termedadirector. However, since it is in close proximity toz thedipole 40 as shown, its function is similar, to that of th'e reector element' 53' and affects the impedance of the dipole 40 on channel 5 and channel 6.,

Iirother words, the effect of the element 56v in conf junction with

reflector elements

52 and 53 is toeven outf the efectiveirnpedance (andthe `elfectivegain) of the antenna array, namely of the resonant folded'dipole 40/as appearing in leads 44transmission line 42to render` the whole effectively close to the design center, namely' 300 ohms irrthepractical embodiment, throughout channels 2 to 6' reception. Thus, the high effectivel gain of the folded 'dipole 40 over channels 2'." to 6'is effectivelymaintainedat its transmission to line 42.with a minimum of mismatch or misphasing and with, accordingly, alow VSWR.`

As stated hereinabove, the arrangement of therdipole element 21, ZZ'and configuration of the rst triangle 28- and .first cross-over point 35' ofzig-zag 20 in conjunction with the length of the harness 45'acts as a closed`stub to reflect animpedance into the folded dipoleftt. Such impedance is made close to the line value, namely of Aline 42,' at. the high endof the lower channels, namely near channel' 6. made by units 2.0, the elfectof such impedance reflected into the antenna 40 is to raise the gain of channel 6-and provide.. a high gain antenna substantially uniformly across channels 2' to6'. In practice, an antenna. construction corresponding to Figure 9 in accordance with thepresent invention has provided. antenna signal gain uniformly-across channels 2 to 6 of the order of 5 to 8 db.

A'further important feature of the antenna array of Figure 9 is the provisionof means to increase the gain on the high channels 7,to 13 of lzig-zag 20 to equalize normal propagation losses. Towards this end, two high channel'phasing elements 57i and 58 are electrically and mechanically securedjto .the transverse bar 50 and parallel with the dipole 401 Elements 57'and'58'are secured between the zig-zag 20 and 'dipole 40 antenna units. The element 57 acts asa reflector in the higher channels while the element 58 serves to block high channel energy from being receivedb'y the center sectionof the large folded dipole,

The effect is to broad'fband'the physical'structure corresponding to zigzag 20, providing effectively. uniform reeeptionover channels 7 to 13'.' In apractical embodiment, actual measurements oflreception were taken vwith an antenna corresponding toFigure 9 and provided a signal` gain of theA order offl4 to l6'dbV over channels 7 to, 13, substantially uniformly. It will bev noted that the gainof the higherchannelsby, the antennal of FigureY 9 is about 6,V or 7 db-higher than. that. provided; by` the lower` channels. It has also beenfound that measure,- mentsof gain in the UHF. channels 14- to.83 with an antennacorrespondingto Figure 9 provided a uniform gainA throughout the UHF band ofthe order of.- 3Y to 4 db,Y being slightly lower thanthat attorded bythe. auf tenna array on channels 2 to 6.

Sincev negligible low frequency pick-up is Nevertheless, lanimportant feature of theinvention is that the lgain at any particular channel throughout...

the television-spectrum ofA channels is hat within, an overall swing of less, than 2 db overthe 6 megacycles ofthe channels. Thus, the antenna structure in accordance with the inventionv are eminently useful for.Y the. re-v ceptionof color,television signals where for truecolor re-V A production the antenna gain lacross each individual chanf nel,cannot varymorethan 2 db. The antennae of the present invention provideA uniform reception throughout, channels 2 to 83 with arvariation within any one channelA of less than 1 db.

The zig-zag 20 asused in the exemplary embodiment of Figure 9 is maintainedin the horizontal plane, and in, generally, thedirectionlof the signals as received 46.

The elements of zig-zagll) are tapered toward the direc-AA tion of the signalsas described and illustrated in connec-V tion with Figure 4 and shownin Figure 7. Such tapering of the zig-zag 20 toward the signal direction broadens ythe bandwidthto provide ,more uniform receptionthat is, reception with asubstantially atresponse over the channels 7 through 13, ,aswell asrfor the UHF channels 14 to 83. Furthermore, ahigher gain and better signalto-noise ratio in such, signalbands occurs with the de scribed zigfzag. The, fiatzig-zag 20 is of a relatively small, size, weight and cost as compared to the prior devices. All the crossfover` points 35, 35 including 3S. are electrically joined` and connected mechanically and electrically. with the cross` bar 50 for grounding. The terminal portions at the

dipole sections

21, 22 connected to the transmissionline 45 are, of course, insulated from the crossover bar 50 and the antenna structure itself.

Figure 10 is a modifiedversion of the antenna array of Figure 9 and embodies the flat plane zig-zag.20 .andv

folded dipole 21V duly interconnected by the transposed transmission section 45` and connected to transmission line 42, together with,the,

reflectors

52, 53 and phasing elements 5.6, 57, 58 between

antennae sections

20 and 40. The antenna array of Figure l0 embodies further a.di. rector 59 ahead; ofthezig-zag section 20. and secured to the transverse bar. Silelectrically and mechanically,

together with asplit reflector 60 transversely supported' across the bar 50k and behind the folded dipole 40. The split reflector 6G` is comprised of three

sections

61, 62, 63 insulated from each other: by

members

64, 65.' The central section 62, of Splitvreector 60l is secured to the cross bar 50 by brackets 66 and electrically grounded therewith. The combination of the split reflectorV 60. andthe director 59 adds high Vfrequency gain to theantenna array, namely improves the signal further in channels 7 to 13 over that of Figure 9. In all othenrespects, the advantages and operationof the antenna of Figure 10 are identical with that of Figure 9, as previously described.

Figure 11 isa modifiedLform of the antenna in accordance with the presentinvention and corresponds essentially to the, antenna illustrated in Figure 9'with'the substitution of an openend conical low band antenna 70 for the folded dipole 40. The conical dipole antenna, 70 is arranged, in a planel perpendicular to that of the cross bar 50 or, in other words, a plane that islvertical or parallel tothe antenna mast 51. The transmissionline interconnecting the flat zig-zag plane 40 with the conical dipole 70 is the transposedtransmission line 45. The rear reflector elements .52,and 53 perform the same function as described for the antenna ofFigure 9, and the phasing,

director elements

71 and 72 correspond tov thev elements 56 to 58of Figure,9 for renderingthe impedance termination of theV antenna array to transmission line 42 close to theV desired value, namely 300 ohms, over. the whole televisionband of channels. The effectiveoperation ofthe array of Figure 1l is comparable to that. of.'

Figure, 9 in all other respects, with the exceptionthat theY folded dipole arrangement` 40' of Figure 9 provides a.

9 better side-to-front rejection of signal than the open ended conical dipole 70. The conical dipole, however, provides excellent UHF reception for the antenna array without any forward angular tilt thereof required.

Figure 12 is still a fu'rther and simplified version of an antenna employing the dat conical zig-zag 20 of the invention. As previously set forth in connection with the description of Figures 4, 7 and 9, the flat tapered unit 20 is structurally designed t0 receive channels 7 to 13 as well as the UHF channels. The liat zig-zag 20 is secured to the metal cross bar 50 of the antenna mast structure, which in turn is secured to the vertical mast 51 by fastening means 51a. .The center of the zigzag structure 20 is grounded along the cross-over point 35 to the mast structure. The zig-zag is connected directly to the transmission line 42 through the lead 44 thereof at the insulated dipole 2.1, 22 section'thereof. In other words, the zig-zag 20 is employed directly as an antenna receiver element and is effective in the embodiment of Figure 12 substantially only for the higher frequencies encompassed by the VHF band, namely channels 7 to 13, as well as the UHF band.

The flat zig-zag reception is improved by the use of the director element 7'5 at the forward portion thereof toward the direction of signal reception 46 and the reflector element 76 at the rear section thereof, both supported by and grounded to the transverse bar 50. Since the structure of Figure 12 is not for the reception of low VHF band channels 2 to 6, the elimination of the low frequency dipoles corresponding to the folded dipole 20 (Figure 9) or the conical dipole 70 (Figure 11) does not disturb the other positive functions and advantages of the zig-zag unit 20 as an antenna per se. The gain, signal-to-noise ratio, polar reception distribution, namely as from front-to-back and side-to-back rejection, is excellent with a uniform reception pattern over the higher channels suitable for color television reception.

While I have disclosed several embodiments, features and factors in conjunction with the invention herein, it is to be understood that modifications are feasible without departing from the broadest spirit and scope of the invention as defined in the following claims.

I claim:

1. A high gain broad band receiving antenna for television signals encompassing the lower VHF band of channels 2 to 6 and the upper VHF band of channels 7 to 13 comprising a dipole section cut to receive channel 2 t0 6 signals; a dat plane zig-zag' section cut to receive channel 7 to 13 signals and the UHF band; said zig-zag section having a'dipole unit with conductive arms extending from the unit ends criss-crossed into a plurality of 'rhombus areas extending from the dipole unit in a single plane with the width of each succeeding rhombus less to constitute a tapered zig-zag array, the cross-over points of said arms being interconnected electrically and grounded; said sections lying substantially in the plane of plarization of the signals to be received; and transmission means interconnecting said dipole sections and said zigzag section in 180 out-of-phase relation whereby the composite reception by said sections is enhanced for the upper VHF band and for the UHF band, and reception by the dipole section of the lower VHF band is substantially unimpeded by the connection thereto of said zig-zag section.

2. A high gain broad band receiving antenna for television signals encompassing the lower VHF band of channels 2 to 6 and the upper VHF band of channels 7 to 13 comprising a conical dipole section cut to receive channel 2 to 6 signals; a flat plane zig-zag section cut to receive channel 7 to 13 signals; said zig-zag section having a dipole unit with conductive arms extending from the unit en ds criss-crossed into a plurality of rhombus areas extending from the dipole unit in a single plane with the width of each succeeding rhombus less to constitute a tapered zig-zag array, the cross-over points ofsaid arms being interconnected electrically and grounded; said sec'- tions lying substantially in the plane of polarization of the signals to be received; and transmission means interconnecting said dipole section and said zig-zag section in 130 out-of-phase relation whereby the composite reception by said sections is enhanced for the upper VHF band; arid reception by the dipole vsection of the lower VHF band is substantially unimpeded by the connection thereto of said zig-zag' section. i y i y 3. A high gain broad band receiving antenna for television signals encompassing the lower VHF band of channels 2 to 6 and the upper VHF band of channels 7 to 13 comprising a folded dipole section cut to receive channel 2 to 6 signals; a flat plane zig-zag section cut to receive channel 7 to 13 signals; said zig-zag section having a dipole unit with conductive arms extending from the unit ends criss-crossed into a plurality of rhombus areas extending from the dipole unit in a single plane with the width of each succeeding rhombus less to constitute a tapered zig-zag array, the cross-over points of said armsA being interconnected electrically and grounded; said sections lying substantially in the plane of polarization of the signals to be received; transmission means interconnecting said dipole sections and said zig-zag sec- `tion in 180 out of phase relation whereby the composite reception by said sections is enhanced for the upper VHF band and for the UHF band, said transmission means and said zig-zag section reflecting a high impedance at the terminals of said dipole section for the lower VHF band signals, whereby reception by the dipole section of the lower VHF band is substantially unimpeded by the connectionl thereto of said zig-zag section; and a plurality of conductive grounded cross arms located near to and parallel with said dipole section, said arms being cut and located to even out the terminal impedance and gain of said antenna across channels 2 to 6.

v 4. A high gain broad band receiving antenna for television signals encompassing the lower VHF band of channels 2 to 6 and the upper VHF band of channels l7 to 13 and the UHF band comprising a dipole section resonant near channel 3 to receive channel Zto 6 signals; a at plane zig-zag section cut to receive channel 7 to 13 signals; said zig-zag section having a dipole unit with conductive arms extending from the unit ends crisscrossed into a plurality of rhombus areas extending v from the dipole unit in a single plane with the width of each succeeding rhombus less to constitute a tapered zig-zag array, the cross-over pointsof said arms being interconnected electrically and grounded; said sections -lying substantially in the plane of polarization of the signals to be received; transmission means interconnecting said dipole section and said zig-zag section in out of phase relation whereby the composite reception by said section is enhanced for the upper VHF band and for `the UHF band, said transmission means and said zig-zag section reflecting a high impedance at the terminals of said dipole section for the lower VHF band signals, whereby reception by the dipole section of the lower VHF band is substantially unimpeded by the connection thereto of said zig-zag section; and a plurality of conductive grounded cross-arms located near to and parallel with said dipole section, said arms being cut and located to even out the terminal impedance and gain of said antenna across channels 2 to 6 and comprising a first reilector tuned to channel 2, a second rellector tuned to channel 3 and a third reflector type unit located between said sections and tuned to channel 5; the overall gain and terminal impedance of the antenna being substantially uniform across any one received television channel to provide fidelity of color signal reception.

5. A high gain broad band receiving antenna for television signals encompassing the lower VHF band of channels 2 to 6 and the upper VHF band of channels 7 to 13 and the UHF band comprising a dipole section resonant near channel 3 to receive channel 2 to 6 Signals; a flat plane zig-zag section cut to receive channel 7 to 13 signals; said Vzig-zag section having adipole unit y with conductivearms. extending from the unit. endscrssecrossed into a plurality of rhombus areas extending from the dipole unit in a single plane with the width of each succeeding rhornbus less to` constitute a tapered zig-zag array, the cross-over points of said arms being interconnected electrically and grounded; said sections lying. substantially in the plane of polarization ofthe signalsy to be received; transmission means interconnecting said dipole section and said zig-zag section in 180 lout of phase relation whereby the composite reception by said section is enhanced for the upper VHF band and for.

the UHF band, said transmission means and said zigf zag section reliecting a high impedance at the terminalsv of said dipole section for the lower VHF band signals, whereby reception bythe dipole section of the lower VHF band is substantially unimpeded by the connectionl thereto of said zig-.zag section; a plurality of conductive, grounded cross-arms located near to andtparallel with said dipole section, said arms beingcut and located to even out the terminal impedance and gain of saidlrantenna across channels 2 to 6 and comprising; ajrst reflector tuned to channel 2a second reflector, tuned to channel 3 anda third reector type unit/.located between said sections and tuned to channel 5; andfapair of grounded conductive cross arms adjacent the., dipole unit of said zig-zag section, said pairrof cross armsbeing cut and located to serve as phasing elements to enhanceV the gain of reception of said zig-zag sectioniuithel upper VHF and UHF bands; the overall gain and terminal impedance of the antenna being substantially uni form across any one received television channelltdprovide fidelity of color.vsignal reception.

6. A highgain broad bandV receiving antenna fortelevision signals encompassingvr the lower VHF band., of channels 2 to 6 and the upper VHF band of channels 7 to 13 and the UHF band comprising a dipolesection resonant near channel 3 toreceive channel V2 to 6 signals; a at plane zig-zag section cut to receive channel A7,to 13 signals; said zig-zag section having a dipole unitwith conductive arms extending from the unit endsncriskscrossed into a plurality .of rhom'bus areas extendingjrom the dipole unit in a single plane with the width `ofgeach succeeding rhombus less to constitute a tapered1zig/-zag array, the ,cross-over. points of said arms being inter,- connected electrically and'grounded;lsaid sectionsglying substantially inthe plane of polarization ofthe signals to be received; transmission means interconnectingsaid dipole section and said zig-zag sectionin 180 outrofV phase relation whereby the composite reception by said 12 section is.enhanced for the upper VHF band andfor thegUHF band, said transmission means and said zigzag section vreflecting a high impedance at the terminals of said dipole section for the lower VHF band signals,

whereby reception by the dipole section of the. lower VHF band is substantially unimpeded 4by the connection thereto of said zig-zag section; a plurality of conductive grounded cross-arms located near to and parallel-with said dipole section, said arms vbeing cut and located to even outthe terminal impedance and gain of said antenna across channels 2 to 6 and comprising a rst reflector tuned to channel 2, a second reflector tuned to channel 3 and a third reector typelunit located between said sections and tuned to channel 5; and a pair of,

grounded conductive cross arms adjacent the dipole unit of said zig-zag section, said pair of cross arms beingV cui;V and located to act as phasing elements to enhancethegain of reception of said zig-zag section to signals inv the upper VHF and UHF bands, and a linear cross element behind said zig-zag section and having two insulated split portions to constitute three conductive alignedrods resonant inthe upper VHF band thereby enhancing4 the,gain of. reception of said zig-zag. section in the upper VHFt and UHFz bands; theoverall gain and terminal impedance of the antenna lbeing, substantiallyuniforrn across, any one; received r television. channel to provide fidelity` of Y color signal reception.

7. Ahighgain receiving antenna for television signals,

References Cited in the le of this patent UNITED STATES PATENTS 2,619,596 Kolster Nov. 25,' 1952 2,638,545; De Peau et al. May l2, 1953 2,700,105 Winegard Jan. 18, 1955 2,701,308 Kay Feb. 1, 1955 OTHER REFERENCES Trio-Radio Electronics, Vol. 23, Issue, 13, page 88,

Oct. 1952.